I would like to run a script after a user login. This script, using his kerberos tickets, will mount an SMB share.
Under RedHat 7 I could simply call the script from /etc/gdm/PreSession/Default and it would run fine. It would even preserve the $KRB5CCNAME when running the script while elevated (this variable is kept via a Defaults env_keep += "KRB5CCNAME" under sudoers.d.
Under Ubuntu 18.04 we use a service under /etc/systemd/user, which would use the ticket whenever there is a ticket.
With other words, under RHEL7 and Ubuntu, we could use the tickets even when elevated via sudo, either by running a user service or by calling the script from /etc/gdm/PreSession/Default.
Under RHEL8 we can't see the variable, neither when running the user service, nor when running it when calling it from /etc/gdm/PreSession/Default. When I log in as the user, I can see the variable, even when using sudo, so the environment variable is kept, but somehow it isn't available for the service nor for that script.
Could anyone help me how to fix this? I think I read somewhere that this might have something to do with how gdm is started under rhel8, but I'm not sure if that's the problem.
UPDATE: I see now that the scripts under /etc/gdm/PreSession/Default execute as root. I had the impression that they were executed as the user.
UPDATE2: It seems that I can use tickets anyway. I was assuming that they were not there, just because the $KRB5CCNAME was unset. But running a command that required the tickets worked anyway.
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